The superfamily of serotonin receptors (5-HT) includes 7 classes (5-HT1-5-HT7) encompassing 14 human subclasses [D. Hoyer, et al., Neuropharmacology, 1997, 36, 419]. The 5-HT6 receptor is the latest serotonin receptor identified by molecular cloning both in rats [F. J. Monsma, et al., Mol. Pharmacol., 1993, 43, 320; M. Ruat, et al., Biochem. Biophys. Res. Commun., 1993, 193, 268] and in humans [R. Kohen, et al., J. Neurochem., 1996, 66, 47].
Compounds with 5-HT6 receptor affinity are useful for the treatment of various disorders of the Central Nervous System and of the gastrointestinal tract, such as irritable intestine syndrome. Compounds with 5-HT6 receptor affinity are also useful in the treatment of anxiety, depression and cognitive memory disorders [M. Yoshioka, et al., Ann. NY Acad. Sci., 1998, 861, 244; A. Bourson, et al., Br. J. Pharmacol., 1998, 125, 1562; D. C. Rogers, et al., Br. J. Pharmacol. Suppl., 1999, 127, 22P; A. Bourson, et al., J. Pharmacol. Exp. Ther., 1995, 274, 173; A. J. Sleight, et al., Behav. Brain Res., 1996, 73, 245; T. A. Branchek, et al., Annu. Rev. Pharmacol. Toxicol., 2000, 40, 319; C. Routledge, et al., Br. J. Pharmacol., 2000, 130, 1606].
Moreover, it has been shown that the 5-HT6 receptor also plays a role in food ingestion [Neuropharmacology, 2001, 41, 210-219]. Food ingestion disorders, particularly obesity, are a serious, fast growing threat to the health of humans of all age groups, since they increase the risk of developing other serious, even life-threatening diseases such as diabetes or coronary diseases.
Several patent documents refer to compounds with affinity for receptors of the 5-HT superfamily. Documents WO 96/23783, WO 96/02537, WO 96/11929 and WO 97/08167 describe heterocyclic compounds antagonists of 5-HT2b/2c.
Surprisingly, the authors of the present invention have observed that tetrahydro-quinoline -sulfonamide compounds with general formula (I) show an affinity for 5-HT6 receptors ranging from good to excellent. These compounds are therefore particularly suitable as pharmacologically active agents in medicaments for the prophylaxis and/or treatment of disorders or diseases related to 5-HT6 receptors.